Abstract

Brachyuran crabs, a bioenergetically significant
group constitute one of the most dominant
macrobenthic faunal components in all the mangrove
ecosystems of the world. Several species of
commercially important crabs like - Scylla serrata
occur in mangroves. Brachyuran crabs play significant
role to maintain the steady state condition of
mangrove ecosystems several ways. The feedig
activities of detritivore crabs such as - Uca,
Macrophthalmus, Dotilla, Sesarma etc. help in the
degradation of organic matter, especially mangrove
litters and decaying woods. They also influence the
functioning of mangrove ecosystems as burrowers
since their repeated burrowing and reburrowing
activities enhance the soil aeration, mixing of different
soil profiles, nutrient cycling, maintaining of fluidity
etc. (Montague, 1980, 1982 ; Bertness, 1985).
Furthermore, crabs create a wide variety of
bioturbation structures which are very significant for
trapping sediments and mangrove seeds (Choudhury
and Choudhury, 1994). In India several taxonomic
works on estuarine and mangrove brachyuran crabs
have been done (Chakraborty et al.,1986; Mandal and
Nandi, 1989; Chakraborty and Choudhury, 1992;
Dev Roy and Das, 2000 etc.). A total of 55 species of
brachyuran crabs under 31 genera have been reported
earlier from the mangrove habitats of India (Dev Roy
and Das, 2000). Eighteen species of brachyuran crabs
under 9 genera and 4 families were identified from
Sundarbans Mangrove Ecosystems (Chakraborty and
Choudhury, 1992).